why this error [nodemon] app crashed - waiting for file changes before starting... code example

Example: [nodemon] app crashed - waiting for file changes before starting...

/* Answer to: "[nodemon] app crashed - waiting for file changes before starting..." */

/*
  This is most likely happening because of all the running server
  process in the background. So just stop them from the terminal.
  
  All you have to do is kill them all by running the command below
  in the terminal then restart nodemon.
*/

  pkill -f node